As is well known, engines require lubricant for their effective operation. With four cycle internal combustion engines, the lubricant is normally supplied to the engine through a recirculating lubricating system wherein the oil is not spent during the operation of the engine. With two cycle engines, on the other hand, the oil is delivered to the engine and is consumed through its lubricating or burned during combustion and any surplus is discharged through the exhaust along with that which has burned. Thus, it is very important to ensure that the amount of lubricant supplied to a two-cycle engine is very accurately controlled so as to minimize the amount of unused oil that will be discharged to the atmosphere through the exhaust.
For that reason, it has been proposed to dispense with or eliminate the previous type of lubricating systems utilized commonly with two-cycle engines wherein the lubricant was mixed with the fuel. In addition to not being as responsive to actual incremental engine running conditions, this mixing of lubricant with the fuel does not always assure that each component of the engine receives proper amounts of lubricant.
There have been proposed, therefore, a number of lubricating systems wherein lubricant is delivered directly to the components of the engine through a delivery system that can be controlled on a cycle-to-cycle basis. These systems generally use reciprocating type pumps that are operated through one or more cycles during one or more revolutions of the engine. By controlling the number of cycles in which the pump is operative, it is possible to control the actual amount of lubricant supplied. If such a pump becomes inoperative or the components stick, however, then dangerous conditions can occur for the engine.
Another problem with these reciprocating type pumps, which are normally electrically operated, is that the circuitry and associated control mechanisms greatly complicate the lubricant system. In addition, the extra components necessary takes up space which, in applications such as outboard motors, may not be available.
It is an object of this invention to provide a lubricant pump and pump control for a lubricant supply system of an engine overcoming the above-stated problems.